One of 20th century music’s most influential and popular artists, Terry Riley created the purest and most enduring expression of minimalist style in In C, which arguably changed the course of contemporary classical music. Present at the genesis of minimalism, Riley was a part of an atmosphere of musical experimentation in the West Coast of the 1960s, and became an important figure for hippy subculture, with an interest in mysticism and Eastern music. Riley’s persistent engagement with improvisation and composition-through-performance challenges the idea of ‘classical music’, as well as the notion of a ‘composer’.

Having studied composition at San Francisco Conservatory and Berkeley, for much of his twenties Riley travelled around Europe and America studying composition privately and supporting himself by playing piano in bars. Back in San Francisco, Riley and others from a West Coast musical scene that included Pauline Oliveros and La Monte Young set up the San Francisco Tape Music Centre. Riley’s early experiments with tape loops and the influence of Young’s Eastern-influenced drone music led to an increasing concern with repetitive and loosely tonal music, fully expressed in his magnum opus, In C.

Premiered at the Tape Music Centre in November 1964, with performers including Steve Reich, Morton Subotnick, Jon Gibson and Oliveros, In C bestowed a cult status upon Riley in the West Coast scene and beyond, intensified by the release of a Columbia recording in 1968. The piece can theoretically be performed by any kind of ensemble, and consists of 53 musical fragments based around a loose C major tonality, instructing players to freely repeat or omit these phrases as desired before proceeding to the next. The resulting polyrhythmic and canonic textures are mesmeric, but the revolutionary implication of the piece is its shifting of the emphasis away from composition, and on to performance. Most of the compositional decisions are left up to the ensemble, prompting a kind of collaborative, improvisational performance alien to many classical musicians. In C has been performed by ensembles as diverse as Bang on a Can and Damon Albarn's Africa Express.

Only a small percentage of Riley’s work can be classed as minimalist, with In C and his Keyboard Studies the only works that strictly come under that definition. However, his output is united under a continued interest in performance and improvisation, with much of his music since the late 1960s not notated. Riley is especially dedicated to improvisation practice at the keyboard, releasing two mesmeric and virtuosic solo albums, Rainbow in Curved Air and Shri Camel in 1969 and 1980 respectively. The latter displays the particular influence an engagement with Indian music has had on his style, both as a performer, having studied with vocal master Prandit Pran Nath, and later as a teacher in universities in India and the US.

In recent years, Riley has been persuaded to return to more traditional forms of composition, especially for string quartet, having met David Harrington of the Kronos Quartet whilst teaching at Mills College. Although this marks a departure from the performance-based practice that defines the core of his output, works such as Salome Dances for Peace possess an improvisational air with an organic sense of structure and wandering, allusive melodic writing. Riley’s wide and eclectic output has been influential across styles and genres, with In C the starting point for many composers, minimalist or otherwise, working in the second half of the 20th century. His experiments with electronics and overdubbing on Rainbow in Curved Air were influential on pop artists such as The Who (acknowledged in their track ‘Baba O’Riley’), and his genre-crossing music absorbing influences from all across the globe has inspired a range of world and fusion artists.